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Search Results: 1 - 10 of 3499 matches for " Seung-Tae Cha "
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Identification of Acceptable Restoration Strategies
Seung-Tae Cha,Nam-Ho Lee,Eung-Bo Shim,Jeong-Hoon Shin
Journal of Systemics, Cybernetics and Informatics , 2008,
Abstract: In recent years, we have seen several catastrophic and cascading failures of power systems throughout the world. Power system breakup and blackouts are rare events. However, when they occur, the effects on utilities and general population can be quite severe. To prevent or reduce cascading sequences of events caused by the various reasons, KEPRI is researching ways to revolutionize innovative strategies that will significantly reduce the vulnerability of the power system and will ensure successful restoration of service to customers. This paper describes a restoration guidelines / recommendations for the KEPS simulator, which allows power system operator and planner to simulate and plan restoration events in an interactive mode. The KEPS simulator provides a list of restoration events according to the priority based on some restoration rules and list of priority loads. Further, the paper will draw on research using information from a Jeju case study.
Ground beetle (Coleoptera: Carabidae) assemblage in the urban landscape, Korea
Jong-Kook Jung,Seung-Tae Kim,Sue-Yeon Lee,Chang-Kyu Park
Journal of Ecology and Field Biology , 2012,
Abstract: This study was conducted with the intention of clarifying the effects of land-use types on a species of ground beetle’s richness,abundance, and composition; the study focused on urban landscapes. We also selected the potential bioindicatorsclassifying land-use types; eleven sites were selected from an urban landscape in Korea. Overall, land-use types in urbanlandscapes did not appear to cause significant decrease in species richness or the abundance of total ground beetle assemblage.According to habitat preferences, several land-use types and distances from the forest significantly affectedthe species richness and abundance, while the open-habitat species were not affected by these variables. Land-use typeswere classified into two major groups, forest and non-forest areas, based on ground beetle assemblage; several indicators,such as Dolichus halensis halensis and subfamily Carabinae species, were of particular consideration. In conclusion, environmentalchange by anthropogenic disturbance can cause different effects on ground beetle assemblages, and forestspecialists can be negatively affected.
Genetic Variation in CYP17A1 Is Associated with Arterial Stiffness in Diabetic Subjects
Soo Jin Yang,Seung-Tae Lee,Won Jun Kim,Se Eun Park,Sung Woo Park,Jong-Won Kim,Cheol-Young Park
Experimental Diabetes Research , 2012, DOI: 10.1155/2012/827172
Abstract: Hypertension and arterial stiffness are associated with an increasing risk of diabetes and cardiovascular diseases. This study aimed to identify genetic variants affecting hypertension and arterial stiffness in diabetic subjects and to compare genetic associations with hypertension between prediabetic and diabetic subjects. A total of 1,069 participants (326 prediabetic and 743 diabetic subjects) were assessed to determine the genetic variants affecting hypertension by analyzing 52 SNPs previously reported to be associated with hypertension. Moreover, the SNPs were tested for association with hemodynamic parameters related to hypertension. Out of the 52 SNPs analyzed, four SNPs including rs5326 (DRD1), rs1004467 (CYP17A1), rs2960306 (GRK4), and rs11191548 (near NT5C2) in diabetic subjects and rs1530440 (C10orf107) in prediabetic subjects showed a modest association with hypertension (, 0.0020, 0.0066, 0.0078, and 0.0015, resp; all were insignificant after Bonferroni correction). Of these SNPs, rs1004467 in CYP17A1 was significantly associated with augmentation index in diabetic subjects who were not taking antihypertensive medication (; corrected ) but not in diabetic subjects receiving antihypertensive medication. This finding suggests that certain genetic variations found in diabetic subjects may confer arterial stiffness and the development of hypertension and also be affected by antihypertensive medication.
CDDO-Imidazolide inhibits growth and survival of c-Myc-induced mouse B cell and plasma cell neoplasms
Seong-Su Han, Liangping Peng, Seung-Tae Chung, Wendy DuBois, Sung-Ho Maeng, Arthur L Shaffer, Michael B Sporn, Siegfried Janz
Molecular Cancer , 2006, DOI: 10.1186/1476-4598-5-22
Abstract: Morphological features and surface marker expression of iMycEμ-2 cells were evaluated using cytological methods and FACS, respectively. mRNA expression levels of the inserted MycHis and normal Myc genes were determined by allele-specific RT-PCR and qPCR. Myc protein was detected by immunoblotting. Cell cycle progression and apoptosis were analyzed by FACS. The expression of 384 "pathway" genes was assessed with the help of Superarray? cDNA macroarrays and verified, in part, by RT-PCR.Sub-micromolar concentrations of CDDO-Im caused growth arrest and apoptosis in iMycEμ-1 and iMycEμ-2 cells. CDDO-Im-dependent growth inhibition and apoptosis were associated in both cell lines with the up-regulation of 30 genes involved in apoptosis, cell cycling, NFκB signaling, and stress and toxicity responses. Strongly induced (≥10 fold) were genes encoding caspase 14, heme oxygenase 1 (Hmox1), flavin-containing monooxygenase 4 (Fmo4), and three members of the cytochrome P450 subfamily 2 of mixed-function oxygenases (Cyp2a4, Cyp2b9, Cyp2c29). CDDO-Im-dependent gene induction coincided with a decrease in Myc protein.Growth arrest and killing of neoplastic mouse B cells and plasma cells by CDDO-Im, a closely related derivative of the synthetic triterpenoid 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid, appears to be caused, in part, by drug-induced stress responses and reduction of Myc.2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO) and closely related derivatives, such as CDDO-imidazolide (CDDO-Im) [1], are novel synthetic triterpenoids that exhibit potent in vitro activity against a wide range of human cancers including lung and ovarian carcinoma [2], acute myeloid leukemia [3], cutaneous T-cell lymphoma [3], chronic lymphocytic leukemia (CLL) [4] and multiple myeloma (MM) [5]. CDDO's anti-neoplastic activity involves a complex set of biochemical pathways that can lead, depending on cell type and context, to induction of cell differentiation and apoptosis [3,5-7], inhibition of
Genetic Variation in CYP17A1 Is Associated with Arterial Stiffness in Diabetic Subjects
Soo Jin Yang,Seung-Tae Lee,Won Jun Kim,Se Eun Park,Sung Woo Park,Jong-Won Kim,Cheol-Young Park
Journal of Diabetes Research , 2012, DOI: 10.1155/2012/827172
Abstract: Hypertension and arterial stiffness are associated with an increasing risk of diabetes and cardiovascular diseases. This study aimed to identify genetic variants affecting hypertension and arterial stiffness in diabetic subjects and to compare genetic associations with hypertension between prediabetic and diabetic subjects. A total of 1,069 participants (326 prediabetic and 743 diabetic subjects) were assessed to determine the genetic variants affecting hypertension by analyzing 52 SNPs previously reported to be associated with hypertension. Moreover, the SNPs were tested for association with hemodynamic parameters related to hypertension. Out of the 52 SNPs analyzed, four SNPs including rs5326 (DRD1), rs1004467 (CYP17A1), rs2960306 (GRK4), and rs11191548 (near NT5C2) in diabetic subjects and rs1530440 (C10orf107) in prediabetic subjects showed a modest association with hypertension ( , 0.0020, 0.0066, 0.0078, and 0.0015, resp; all were insignificant after Bonferroni correction). Of these SNPs, rs1004467 in CYP17A1 was significantly associated with augmentation index in diabetic subjects who were not taking antihypertensive medication ( ; corrected ) but not in diabetic subjects receiving antihypertensive medication. This finding suggests that certain genetic variations found in diabetic subjects may confer arterial stiffness and the development of hypertension and also be affected by antihypertensive medication. 1. Introduction Hypertension is a major health concern that is increasing worldwide [1] and is associated with an increasing risk of developing diabetes and kidney and cardiovascular diseases [2, 3]. The etiology of hypertension is complex in that both genetic and environmental factors influence its development. So far, enormous efforts have been made to identify common genetic variants affecting hypertension by conducting several large-scale genomewide association (GWA) studies including the Wellcome Trust Case Control Consortium (WTCCC) study and the Framingham Heart Study 100K Project [4–7]. However, to our knowledge, no studies have reported a genetic association with hypertension relating to diabetes. Given that numerous genes are known to be associated with hypertension and the prevalence of hypertension in diabetic subjects is relatively high, it is likely that allele variations for multiple genes previously reported to be associated with hypertension may also influence the development of hypertension in the diabetic population. In addition, it is possible that there will be different patterns of association with developing hypertension
NF-κB/STAT3/PI3K signaling crosstalk in iMycEμ B lymphoma
Seong-Su Han, Hwakyung Yun, Dong-Ju Son, Van S Tompkins, Liangping Peng, Seung-Tae Chung, Joong-Su Kim, Eun-Sung Park, Siegfried Janz
Molecular Cancer , 2010, DOI: 10.1186/1476-4598-9-97
Abstract: Nuclear factor-κB (NF-κB) and signal transducer and activator of transcription 3 (STAT3) were constitutively activated in iMycEμ mice, not only in LBLs but also in the splenic B-lymphocytes of young animals months before tumors developed. Moreover, inhibition of either transcription factor in iMycEμ-1 cells suppressed growth and caused apoptosis, and the abrogation of NF-κB activity reduced DNA binding by both STAT3 and Myc, as well as Myc expression. Inhibition of STAT3 signaling eliminated the activity of both NF-κB and Myc, and resulted in a corresponding decrease in the level of Myc. Thus, in iMycEμ-1 cells NF-κB and STAT3 are co-dependent and can both regulate Myc. Consistent with this, NF-κB and phosphorylated STAT3 were physically associated with one another. In addition, LBLs and iMycEμ-1 cells also showed constitutive AKT phosphorylation. Blocking AKT activation by inhibiting PI3K reduced iMycEμ-1 cell proliferation and caused apoptosis, via downregulation of NF-κB and STAT3 activity and a reduction of Myc levels. Co-treatment with NF-κB, STAT3 or/and PI3K inhibitors led to additive inhibition of iMycEμ-1 cell proliferation, suggesting that these signaling pathways converge.Our findings support the notion that constitutive activation of NF-κB and STAT3 depends on upstream signaling through PI3K, and that this activation is important for cell survival and proliferation, as well as for maintaining the level of Myc. Together, these data implicate crosstalk among NF-κB, STAT3 and PI3K in the development of iMycEμ B-cell lymphomas.Deregulated NF-κB activity plays a critical role in the survival and radiation resistance of tumor cells in a variety of human neoplasias including B cell lymphomas (BCLs) [1-5]. NF-κB comprises a family of transcription factors that control genes implicated in B-cell activation, proliferation and resistance to apoptosis [6]. Five known, structurally conserved members of the NF-κB/Rel family function as dimers in various combinations:
Performance of whole-blood interferon-gamma release assay in patients admitted to the emergency department with pulmonary infiltrates
Yoon Lee, Jaehee Lee, Yi Kim, Dong Won, Seung Cha, Jae Park, Tae Jung, Chang Kim
BMC Infectious Diseases , 2011, DOI: 10.1186/1471-2334-11-107
Abstract: The patients with pulmonary infiltrates who received a QuantiFERON (QFT) test in the ED were included as an inpatient group and were divided into TB and non-TB group based on the final diagnosis. Patients with pulmonary TB who were tested in the outpatient department served as a control group.In total, 377 QFT tests were analyzed. Of the 284 inpatient QFT tests, 29.6% had an indeterminate result (35.2% in the 196 patients with non-TB and 17.0% in the 88 patients with TB). In contrast, only 1.1% of the 93 outpatients with TB returned an indeterminate result (p < 0.001). The indeterminate QFT results in the inpatient group were independently associated with lymphocytopenia, hypoalbuminemia, and high C-reactive protein levels. Non-positive QFT results in inpatients with TB were associated with lymphocytopenia and hypoalbuminemia, while non-positive QFT results in outpatients with TB were associated with high erythrocyte sedimentation rates and radiographically more severe diseases.QFT tests in ED-based inpatients with pulmonary infiltrate return indeterminate results relatively frequently. In addition, inpatients and outpatients with pulmonary TB may differ in terms of the risk factors on non-positive QFT results.The whole-blood interferon-gamma release assay (IGRA) is a new type of rapid, immune-based blood test that has significantly aided the diagnosis of tuberculosis (TB) infection [1-3]. However, since the test measures an immunological response, its performance is likely to be affected by differences in mycobacterial activity and factors that suppress the host's immune system, in particular cellular immunity. Indeed, we often encounter patients whose IGRA has returned an indeterminate result. The high rate of indeterminate results has led to concern about using new IGRAs, especially when dealing with patients whose cellular immunity is likely to be impaired [4,5]. However, to date, few studies have sought to identify the factors that are associated with the indet
Experimental Study of the Fry-Drying Phenomena of Organic Wastes in Hot Oil for Waste-Derived Solid Fuel  [PDF]
Tae-In Ohm, Jong-Seung Chae, Seung-Hyun Moon
Journal of Environmental Protection (JEP) , 2014, DOI: 10.4236/jep.2014.57065
Abstract:

In sludge treatment, drying sludge using typical technology with high water content to a water content of approximately 10% is always difficult because of adhesive characteristics of sludge in drying. Many methods have been applied, including direct and indirect heat drying, but these approaches of reducing water content to below 40% after drying are very inefficient in energy utilization of drying sludge. In this study, fry-drying technology with a high heat transfer coefficient of approximately 500 W/m2·°C was used to dry swine excreta, sewage and industrial sludge. Also waste oil was used in the fry-drying process, and because the oil’s boiling point is between 240°C and 340°C and the specific heat is approximately 60% of that of water. In the fry-drying system, the sludge is input by molding it into a designated form after heating the waste oil at temperatures between 130°C and 150°C. At these temperatures, the heated oil rapidly evaporates the water contained in the sludge, leaving the oil itself. After approximately 8 - 10 min, the water content of the sludge was less than 10%, and its heating value surpassed 20,000 kJ/kg. Indeed, this makes the organic sludge appropriate for use as a solid fuel. The dried swine excreta, sewage and industrial sludge can be used in an incinerator like low-rank coal or solid fuel.

SPH with radiative transfer: method and applications
Pierre Bastien,Seung Hoon Cha,Serge Viau
Revista mexicana de astronomía y astrofísica , 2004,
Abstract:
An alternative origin for debris rings of planetesimals
Sergei Nayakshin,Seung-Hoon Cha
Physics , 2012, DOI: 10.1111/j.1365-2966.2012.21003.x
Abstract: Core Accretion, the most widely accepted scenario for planet formation, postulates existence of km-sized solid bodies, called planetesimals, arranged in a razor-thin disc in the earliest phases of planet formation. In the Tidal Downsizing hypothesis, an alternative scenario for formation of planets, grain growth, sedimentation and formation of planetary cores occur inside dense and massive gas clumps formed in the outer cold disc by gravitational instability. As a clump migrates inward, tidal forces of the star remove all or most of the gas from the clump, downsizing it to a planetary mass body. Here we argue that such a clump may form not only the planetary core but also numerous smaller bodies. As an example, we consider the simplest case of bodies on circular orbits around the planetary core in the centre of the gas clump. Bodies smaller than 1 km suffer a strong enough aerodynamic drag, spiral in and accrete onto the solid core rapidly; bodies in the planetesimal size range lose their centrifugal support very slowly. We find that planetesimals orbiting the protoplanetary core closely remain gravitationally bound to it; these may be relevant to formation of satellites of giant planets. Planetesimals on more distant orbits within the host clump are unbound from the protoplanet and are set on mildly eccentric heliocentric orbits, generically forming wide rings. These may correspond to debris discs around main sequence stars and the Kuiper belt in the Solar System. For the latter in particular, our hypothesis naturally explains the observed sharp outer edge and the "mass deficit" of the Kuiper belt.
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